Research

Recent and ongoing research projects which I lead as a primary chief investigator :

The Impact of Prenatal Alcohol Exposure on Longevity and Cancer Incidence: Evidence from Prohibition in Canada (Abdelhady, Mohamed (Primary Chief Investigator (PCI)), Louis-Philippe Béland (Partner Investigator (PI)), and Vincent O’Sullivan (Chief Investigator (CI))).

This paper estimates the causal impact of in utero alcohol exposure on long-term health outcomes: longevity and chronic health outcomes. We exploit the staggered adoption and repeal of Canadian provincial prohibition between 1916 and 1930, which generated quasi-experimental reductions in alcohol access. Using the 1991 Canadian Census Health and Environment Cohort (CanCHEC) linking long-form census data to administrative records on mortality and cancer, and the 2000–2002 Canadian Community Health Survey linked to Vital Statistics and the Canadian Cancer Registry, we estimate a difference-in-differences model comparing individuals exposed to prohibition while in utero with those born in provinces where alcohol remained legal (wet provinces) before and after prohibition. We find that alcohol prohibition during gestation improves long-term health outcomes, increasing longevity and reducing the risk of cancer, cerebrovascular disease, and dementia.

The Impact of Prenatal Alcohol Exposure on Educational Attainment and Earnings: Evidence from Prohibition in Canada (Abdelhady, Mohamed (Primary Chief Investigator (PCI)), Louis-Philippe Béland (Partner Investigator (PI)), and Vincent O’Sullivan (Chief Investigator (CI))).

This paper estimates the causal impact of in utero alcohol exposure on long-term educational attainment and adult earnings. We exploit the staggered adoption and repeal of Canadian provincial alcohol prohibition between 1916 and 1930, which reduced alcohol access during pregnancy. Using the 1971 Canadian Census, we estimate a difference-in-differences model comparing individuals exposed to prohibition while in utero with those born in provinces where alcohol remained legal (wet provinces) before and after prohibition. We find that alcohol prohibition during gestation increases primary and secondary school completion and raises earnings measured in 1971, when exposed cohorts are in their forties and fifties. The largest earnings gains are concentrated in the lower part of the income distribution. These findings highlight the role of prenatal conditions, maternal health policy and alcohol regulations in shaping long-term human capital and labour market outcomes.

The Impact of Prenatal and Childhood Smoke Exposure on Birth Outcomes and Pediatric Cancer: Evidence from In-Vehicle Smoking Bans in Canada (Abdelhady, Mohamed).

This paper estimates the causal impact of in utero and early-childhood exposure to second-hand smoke on birth and pediatric health outcomes. We exploit the staggered implementation of smoking bans in vehicles with children across Canada between 1996 and 2021, which generated quasi-experimental reductions in exposure. Using the nationwide Peds CCR–DAD–VS–T1FF linkage (≈11 million births), we construct gestational and early-childhood exposure windows and harmonize oncologic outcomes to estimate policy-induced changes in birthweight, infant mortality, and pediatric cancer. We find that reduced exposure to second-hand smoke improves birth outcomes and lowers the incidence of several pediatric cancers, including lymphoid leukemia, thyroid carcinoma, nasopharyngeal carcinoma, and intracranial tumors.

The Effect of Smoke Exposure on Birthweight, Infant Mortality, and Pediatric Cancer Outcomes: Evidence from Canadian Wildfires (Abdelhady, Mohamed and Erin Strumpf).

This paper estimates the causal impact of gestational exposure to wildfire smoke on birth and early-life health outcomes. We exploit major wildfires across Canada between 2001 and 2019, which generated quasi-experimental increases in fine particulate matter (PM₂.₅) and co-pollutants. Using the nationwide Peds CCR–DAD–VS–T1FF linkage (≈11 million births), combined with postal-code–level environmental exposures from CANUE and NOAA’s Hazard Mapping System, we construct trimester- and month-specific exposure windows and harmonize pediatric cancer and perinatal outcomes to estimate the effects of wildfire smoke on birthweight, stillborn incidence, infant mortality (<1 year), and pediatric cancer. We also assess heterogeneity by maternal socioeconomic status and critical prenatal windows. This project provide the first large-scale, nationally representative evidence of the long-term health consequences of prenatal wildfire smoke exposure, particularly on rare but serious outcomes like childhood cancer.

A Natural Experiment on the Effect of HPV Vaccination on Cancer Incidence among Canadian Women (Abdelhady, Mohamed).

This paper estimates the causal impact of adolescent HPV vaccination on subsequent HPV-related cancer incidence among women. We exploit the staggered introduction of school-based HPV immunization programs across Canadian provinces, with eligibility sharply defined by cohort and grade at rollout, generating quasi-experimental variation in exposure. Using the 2021 Census linked to the Canadian Cancer Registry and provincial program data, we implement two complementary designs. First, a regression discontinuity compares women just eligible versus just ineligible at the birthdate or grade cutoffs specific to each province-year. Second, a province-by-cohort difference-in-differences contrasts eligible cohorts in adopting provinces with same-aged cohorts in provinces not yet implementing the program. I focus on HPV-related malignancies, including cervical, vulvar, vaginal, and oropharyngeal cancers. These findings provide the first nationally representative, causal evidence on the long-term cancer-preventive effects of adolescent HPV vaccination.